Process for the manufacturing of joining profiles

ABSTRACT

A process for the manufacturing of longitudinal profiles such and tongue and groove on boards wherein the process includes the steps;  
     a) Moulding a substantial part of the profile cross-section by means of milling with a milling tool.  
     b) Fine moulding undercuts in at least the groove of the board by means of broaching utilising at least one broaching tool.

[0001] Different kinds of boards and other flat elements which arejoined to each other by means of tongue and groove are well known.Tongue and groove are nowadays normally made by milling which is arational method. It is however difficult to achieve complexcross-sections with undercuts with traditional milling, especially innarrow grooves. It is known to achieve undercuts to some degree byutilising more than one milling tool with different rotation axis. Theproblem with this method is however that it is very difficult to obtaindesirable tolerances due to vibrations and flexing in the machine sincethere must be some distance between the different milling tools. Thecross-section possible to manufacture by this method is also limitedsince the milling tool will have to rotate through the opening of forexample a groove. It is desirable to achieve a process where thetolerance play is good, undercuts with sharper angles are possible tomanufacture and where dust and particles form the milling isn'tobstructing the process.

[0002] It has, according to the process of the present invention, beenmade possible to achieve profiles such as tongue and groove on boards,with better tolerances, undercuts with sharper angles and without havingdust and particles from the milling process obstructing the process.

[0003] Accordingly, the invention relates to a process for themanufacturing of longitudinal profiles such and tongue and groove onboards wherein the process includes the steps;

[0004] a) Moulding a substantial part of the profile cross-section bymeans of milling with a milling tool.

[0005] b) Fine moulding undercuts in at least the groove of the board bymeans of broaching utilising at least one broaching tool.

[0006] The milling tool is adjustably fixed in a conveying machine,which machine feeds the boards past the milling tool during the millingoperation. The broaching tool is preferably adjustably fixed in the sameconveying machine, which machine feeds the board past the broachingtool. The process is most suitably used for machining tongue and grooveon thin boards such as floor boards. The tongue and groove may, throughthe process, be provided with a functionality which allows them to snapjoin. Accordingly, the moulding of the profiles is initiated by millinga substantial part of the material to be removed with a traditionalmilling tool. The final shape of the profiles are then achieved bybroaching. The undercuts are also achieved in the broaching stage of theprocess.

[0007] If materials like fibre board or particle board are used it knownthat burrs often occur which will obstruct the functionality in thetighter parts of a snap joint. This can be avoided by adding the stepcoating of the milled profile section before the broaching stage wherethe fine moulding takes place. The coating suitably comprises asubstance selected from the group; wax, oil a polymeric material beingexemplified by a thermoplastic polyolefin and a lacquer beingexemplified by a UV-curing lacquer.

[0008] The broaching tool preferably comprises broaching edges, abroaching body and a broaching clamp. The broaching body is suitablyprovided with internal cooling channels for a cooling media, the coolingmedia being selected from the group consisting of a gas and a liquid.The broaching body is suitably also provided with a temperature sensorused for guiding the cooling. The temperature sensor is either aninfrared sensor directed towards one or more broaching edges or aconductive sensor attached to the broaching body. The broaching tool issuitably provided with at least one nozzle for blowing air on thebroaching edges. The air blown on the broaching edges may serve twopurposes the first one being to remove dust and particles from thecutting edges the second one being to cool the broaching tool. It ispossible to use the blown air as either a complement to, or areplacement for the internal cooling. The broaching tool is suitablyalso provided with an air and dust evacuation duct which evacuates dustand particles from the broaching edges. The air blown on the edges maysuitably also pulsate for better cleaning of the edges.

[0009] The front edge portions of the broaching edges are suitablyconcave in order to increase the stability during the cutting operationand at the same time ensure secure removal of the waste material so thatno or very little burr is formed. The side edge portions of thebroaching edges are suitably also concave in order to increase thestability during the cutting operation and at the same time ensuresecure removal of the waste material so that no or very little burr isformed.

[0010] The invention is described further in connection to the encloseddrawings showing different embodiments of the invention whereby,

[0011]FIG. 1a-1 d shows, in a cross-section perspective view, alongitudinal profile 2 in the form of a groove 2″ in an edge of a board1 at different steps in the process according to one embodiment of theinvention.

[0012]FIG. 2a-2 d shows, in a cross-section perspective view, alongitudinal profile 2 in the form of a tongue 2′ in an edge of a board1 at different steps in the process according to one embodiment of theinvention.

[0013]FIG. 3a-3 d shows, in a cross-section perspective view, alongitudinal profile 2 in the form of a groove 2″ in an edge of a board1 at different steps in the process according to a second embodiment ofthe invention.

[0014]FIG. 4a-4 d shows, in a cross-section perspective view, alongitudinal profile 2 in the form of a tongue 2′ in an edge of a board1 at different steps in the process according to a second embodiment ofthe invention.

[0015]FIG. 5 shows, in cross-section perspective view, a broaching tool3 for fine moulding undercuts 20 in a tongue 2′.

[0016]FIG. 6 shows, in cross-section perspective view, a broaching tool3 for fine moulding undercuts 20 in a groove 2″.

[0017] Accordingly FIG. 1a-1 d shows, in a cross-section perspectiveview, a longitudinal profile 2 in the form of a groove 2″ in an edge ofa board 1 at different steps in the process according to one embodimentof the invention. The drawing is simplified by enlarging certain objectsin the cross-section geometry in order to enhance the understanding ofthe invention. FIG. 1a shows a board 1 with a core and a decorative toplayer before the moulding of the longitudinal profile 2. FIG. 1b showsthe board 1 after milling of a substantial part of a groove 2″. The mainpart of the material to be removed in the making of the finished groove2″ is here removed by a traditional rotating milling tool. Such a toolis well suited for removing larger quantities of material as the toolitself will convey the material from the groove 2″. FIG. 1c shows theboard 1 after applying an impregnation 4 on the edge. It is advantageousto apply the impregnation 4 at the stage after milling since theimpregnation 4 only will penetrate to a certain distance from thesurface. It is possible to utilise several known substances for thisimpregnation where oil and wax are the most commonly used. FIG. 1d showsthe board 1 after the fine moulding by broaching utilising a broachingtool 3 similar to the one shown in FIG. 6. The impregnation applied inthe earlier stage of the process will act as a lubricant as well as abonding agent which will make the surface of the joint smoother and atthe same time minimise the risk for forming of burr. The later is arather common problem, specially in cases where the core of the board 1is made of fibre board like MDF (medium density fibre board) or HDF(high density fibre board). A smoother and more well defined surface incritical parts of a joint will render the possibility to design thejoint with a decreased play. This, in its turn, will render thepossibility to make smaller undercuts 20 and hooks 21 with maintainedtearing resistance or increasing the tearing resistance by maintainingthe dimension of the undercuts 20 and hooks 21. The advantages withbroaching is furthermore that it will be possible to manufactureprofiles 2 with cross-section geometry impossible to manufacture withtraditional milling, as the one performed in earlier stages of theinvention.

[0018]FIG. 2a-2 d shows, in a cross-section perspective view, alongitudinal profile 2 in the form of a tongue 2′ in an edge of a board1 at different steps in the process according to one embodiment of theinvention. The drawing is simplified by enlarging certain objects in thecross-section geometry in order to enhance the understanding of theinvention. FIG. 2a shows a board 1 with a core and a decorative toplayer before the moulding of the longitudinal profile 2. FIG. 2b showsthe board 1 after milling of a substantial part of a tongue 2′. The mainpart of the material to be removed in the making of the finished tongue2′ is here removed by a traditional rotating milling tool. Such a toolis well suited for removing larger quantities of material as the toolitself will convey the material from the tongue 2′. FIG. 2c shows theboard 1 after applying an impregnation 4 on the edge. It is advantageousto apply the impregnation 4 at the stage after milling since theimpregnation 4 only will penetrate to a certain distance from thesurface. It is possible to utilise several known substances for thisimpregnation where oil and wax are the most commonly used. FIG. 2d showsthe board 1 after the fine moulding by broaching utilising a broachingtool 3 similar to the one shown in FIG. 5. The impregnation applied inthe earlier stage of the process will act as a lubricant as well as abonding agent which will make the surface of the joint smoother and atthe same time minimise the risk for forming of burr. The later is arather common problem, specially in cases where the core of the board 1is made of fibre board like MDF (medium density fibre board) or HDF(high density fibre board). A smoother and more well defined surface incritical parts of a joint will render the possibility to design thejoint with a decreased play. This, in its turn, will render thepossibility to make smaller undercuts 20 and hooks 21 with maintainedtearing resistance or increasing the tearing resistance by maintainingthe dimension of the undercuts 20 and hooks 21. The advantages withbroaching is furthermore that it will be possible to manufactureprofiles 2 with cross-section geometry impossible to manufacture withtraditional milling, as the one performed in earlier stages of theinvention.

[0019]FIG. 3a-3 d shows, in a cross-section perspective view, alongitudinal profile 2 in the form of a groove 2″ in an edge of a board1 at different steps in the process according to a second embodiment ofthe invention. The drawing is simplified by enlarging certain objects inthe cross-section geometry in order to enhance the understanding of theinvention. FIG. 3a shows a board 1 with a core and a decorative toplayer before the moulding of the longitudinal profile 2. FIG. 3b showsthe board 1 after milling a groove 2″. More material than the finalshape of the groove 2″ is here removed by a traditional rotating millingtool. Such a tool is well suited for removing larger quantities ofmaterial as the tool itself will convey the material from the groove 2″.FIG. 3c shows the board 1 after applying a polymeric material 5 to thegroove 2″. The polymeric material 5 may suitably be a thermoplasticmaterial which is molten and applied in the groove 2″ in a process whichreminds of extrusion. In cases where the board 1 is used as a floorcovering material the thickness of the board 1 will be in the range 5-12mm. The thickness of the polymeric material 5 applied will then have tobe in the range 0.6-1.5 mm in order to match the geometry of the joint.A thermoplastic material applied in a molten state will have to becooled before final steps of the moulding of the joint. This may beachieved by blowing cooled air and/or by pressing a cooling slider of athermally conductive material towards the joint. The latter may also beused for pre shaping the polymeric material 5 before the final finemoulding. FIG. 3d shows the board 1 after the fine moulding by broachingutilising a broaching tool 3 similar to the one shown in FIG. 6. Thepolymeric material 5 applied in the earlier stage of the process willmake the surface of the joint smoother and at the same time minimise therisk for forming of burr. The later is a rather common problem,specially in cases where the core of the board 1 is made of fibre boardlike MDF (medium density fibre board) or HDF (high density fibre board).A smoother and more well defined surface in critical parts of a jointwill render the possibility to design the joint with a decreased play.This, in its turn, will render the possibility to make smaller undercuts20 and hooks 21 with maintained tearing resistance or increasing thetearing resistance by maintaining the dimension of the undercuts 20 andhooks 21. The advantages with broaching is furthermore that it will bepossible to manufacture profiles 2 with cross-section geometryimpossible to manufacture with traditional milling, as the one performedin earlier stages of the invention.

[0020]FIG. 4a-4 d shows, in a cross-section perspective view, alongitudinal profile 2 in the form of a tongue 2′ in an edge of a board1 at different steps in the process according to a second embodiment ofthe invention. The drawing is simplified by enlarging certain objects inthe cross-section geometry in order to enhance the understanding of theinvention. FIG. 4a shows a board 1 with a core and a decorative toplayer before the moulding of the longitudinal profile 2. FIG. 4b showsthe board 1 after milling a tongue 2′. More material than the finalshape of the tongue 2′ is here removed by a traditional rotating millingtool. Such a tool is well suited for removing larger quantities ofmaterial as the tool itself will convey the material from the tongue 2′.FIG. 4c shows the board 1 after applying a polymeric material 5 to thetongue 2′. The polymeric material 5 may suitably be a thermoplasticmaterial which is molten and applied on the tongue 2′ in a process whichreminds of extrusion. In cases where the board 1 is used as a floorcovering material the thickness of the board 1 will be in the range 5-12mm. The thickness of the polymeric material 5 applied will then have tobe in the range 0.6-1.5 mm in order to match the geometry of the joint.A thermoplastic material applied in a molten state will have to becooled before final steps of the moulding of the joint. This may beachieved by blowing cooled air and/or by pressing a cooling slider of athermally conductive material towards the joint. The latter may also beused for pre shaping the polymeric material 5 before the final finemoulding. FIG. 4d shows the board 1 after the fine moulding by broachingutilising a broaching tool 3 similar to the one shown in FIG. 5. Thepolymeric material 5 applied in the earlier stage of the process willmake the surface of the joint smoother and at the same time minimise therisk for forming of burr. The latter is a rather common problem,specially in cases where the core of the board 1 is made of fibre boardlike MDF (medium density fibre board) or HDF (high density fibre board).A smoother and more well defined surface in critical parts of a jointwill render the possibility to design the joint with a decreased play.This, in its turn, will render the possibility to make smaller undercuts20 and hooks 21 with maintained tearing resistance or increasing thetearing resistance by maintaining the dimension of the undercuts 20 andhooks 21. The advantages with broaching is furthermore that it will bepossible to manufacture profiles 2 with cross-section geometryimpossible to manufacture with traditional milling, as the one performedin earlier stages of the invention.

[0021]FIG. 5 shows, in cross-section perspective view, a broaching tool3 for fine moulding undercuts 20 in a tongue 2′. The broaching tool 3shown in FIG. 5 is a simplified version of the broaching tool 3 used toachieve the profile 2 cross-sections shown in FIG. 2d and 4 d above. Thebroaching tool 3 is used for fine moulding the tongue 2′ so that hooks21 and a good matching of a groove 2″, manufactured according to thepresent invention, are achieved. The broaching is initiated after havingmilled a substantial part of the tongue 2′ so that most of the materialto be removed in order to obtain a tongue 2′ as shown in selectedembodiments of the invention, is removed by the milling process ensuringa more secure operation in the broaching stage. The broaching tool 3 isadjustably fixed in the conveying machine, which machine feeds the boardpast the broaching tool 3.

[0022] The broaching tool 3 comprises broaching edges 31, a broachingbody 32 and a broaching clamp. The broaching body 32 is provided withinternal cooling channels for a cooling media. The cooling media may begas and a liquid. A temperature sensor used for guiding the coolingbroaching body 32 is advantageously also used. The manufacturingtolerances will be better if the temperature in the broaching tool 3 ismaintained within a selected range. The temperature sensor may be aninfrared sensor directed towards one or more broaching edges 31 or aconductive sensor attached to the broaching body 32 itself. It alsopossible to achieve a narrow temperature range in the broaching tool 3by controlling the temperature of the cooling media. The broaching tool3 may also be provided with one or more nozzles blowing air on thebroaching edges 31. The air stream is adjusted so that it will cool thebroaching edges 31 as well as removing dust and particles from the same.The broaching tool 3 may furthermore be provided with an air and dustevacuation duct which evacuates dust and particles from the broachingtool 3. The air blown on the broaching edges 31 suitably pulsates forimproved cleaning of the broaching edges 31.

[0023] The front edge portions 31′ and the side edge 31″ portions of thebroaching edges 31 are concave in order to increase the stability duringthe cutting operation and at the same time ensure secure removal of thewaste material so that no, or very little burr is formed.

[0024]FIG. 6 shows, in cross-section perspective view, a broaching tool3 for fine moulding undercuts 20 in a groove 2″. The broaching tool 3shown in FIG. 6 is a simplified version of the broaching tool 3 used toachieve the profile 2 cross-sections shown in FIG. 1d and 3 d above. Thebroaching tool 3 is used for fine moulding the groove 2″ so thatundercuts 20 and a good matching of a tongue 2′, manufactured accordingto the present invention, are achieved. The broaching is initiated afterhaving milled a substantial part of the groove 2″ so that most of thematerial to be removed in order to obtain a groove 2″ as shown inselected embodiments of the invention, is removed by the milling processensuring a more secure operation in the broaching stage. The broachingtool 3 is adjustably fixed in the conveying machine, which machine feedsthe board past the broaching tool 3.

[0025] The broaching tool 3 comprises broaching edges 31, a broachingbody 32 and a broaching clamp. The broaching body 32 is provided withinternal cooling channels for a cooling media. The cooling media may begas and a liquid. A temperature sensor used for guiding the coolingbroaching body 32 is advantageously also used. The manufacturingtolerances will be better if the temperature in the broaching tool 3 ismaintained within a selected range. The temperature sensor may be aninfrared sensor directed towards one or more broaching edges 31 or aconductive sensor attached to the broaching body 32 itself. It alsopossible to achieve a narrow temperature range in the broaching tool 3by controlling the temperature of the cooling media. The broaching tool3 may also be provided with one or more nozzles blowing air on thebroaching edges 31. The air stream is adjusted so that it will cool thebroaching edges 31 as well as removing dust and particles from the same.The broaching tool 3 may furthermore be provided with an air and dustevacuation duct which evacuates dust and particles from the broachingtool 3. The air blown on the broaching edges 31 suitably pulsates forimproved cleaning of the broaching edges 31.

[0026] The front edge portions 31′ and the side edge 31″ portions of thebroaching edges 31 are concave in order to increase the stability duringthe cutting operation and at the same time ensure secure removal of thewaste material so that no, or very little burr is formed.

[0027] The invention is not limited by the embodiments shown since itcan be varied in different ways within the scope of the invention. Itfor example possible to moulding a substantial part of the profile 2 bymilling followed by fine moulding by broaching without an intermediateimpregnation or coating as shown in selected embodiments of theinvention. It is also possible to apply impregnation or coating at laterstages of the process.

1-18. Cancelled.
 19. A longitudinal profile made by a processcomprising, a) moulding a substantial part of the profile cross-sectionby means of milling with a milling tool, and b) fine moulding undercutsin at least the groove of the board by means of broaching utilising atleast one broaching tool.
 20. A system for forming a surface comprisinga plurality of boards, the system comprising: a first board havingedges, at least one of the edges comprising a projecting tongue; and asecond board having edges, at least one of the edges comprising adepressed groove; wherein at least one of the tongue and the groovecomprise a milled polymeric material, such that tongue and the grooveare shaped to form a joint.
 21. The system of claim 20, wherein thetongue and the groove both comprise a milled polymeric material.
 22. Thesystem of claim 20, wherein at least one of the tongue and the groove isglued to a core of the board.
 23. The system of claim 20, wherein thepolymeric material is selected from the group consisting ofthermoplastic and lacquer.
 24. The system of claim 20, wherein thepolymeric material has been formed by extrusion before being milled. 25.The system of claim 20, wherein at least one of the first board and thesecond board comprises a core, the core being formed from wood fiberboard.